While double clicking the pas file to open it in Delphi XE4 IDE, I am getting this error:
XML Parse Error:
Reason: The system cannot locate the object specified
This file uses xmldom, XMLIntf, oxmldom, XMLDoc units in its uses clause. I have changed nothing in this file and this opens up with no error in Delphi 7, but in Delphi XE4, its throwing above error when I double click .pas file to open it in IDE. After pressing OK, the .dfm file opens up.
Opening the .pas and .dfm files does not involve XML parsing. The fact that your unit uses some XML related units also does not involve parsing of XML at unit load time.
So this sounds like the IDE has a problem opening some auxiliary file associated with the source file. And something about this file or its reference in the source has not survived the transition from XE4. Look for files with the same stem as the troublesome source unit, but a different extension. Or look for IDE generated {...} comments in the source unit that refer to auxiliary files. This should hopefully lead you to a solution.
